Ultrasonic trapping of paramecia and estimation of their locomotive force

Abstract

Ultrasonic trapping of locomotive organisms was studied by using paramecia of ∼0.2 mm size. An ultrasonic standing wave of ∼3 MHz was generated in a sample cell to trap the paramecia. When the ultrasonic oscillation was turned on, paramecia began to swim along the nodes of the standing wave. Furthermore, when two ultrasonic waves were crossed orthogonally in a thin sample cell, paramecia were trapped at the lattice points of the nodes. The trapping efficiency increased with the ultrasonic power density. The locomotive force of the paramecia was estimated from the threshold power density for trapping.

The polarization response in InAs quantum dots: theoretical correlation between composition and electronic properties

“…For example, semiconductor optical amplifiers (SOAs) for telecommunications require engineered QDs for isotropic polarization behavior 2,4,5 . Polarization control is also crucial for other applications, such as polarization-entangled photons emitted by single QDs 3 and polarization sensitive applications of vertical cavity surface emitting lasers 7,8 .…”

Dexterous manipulation of microparticles using Bessel-function acoustic pressure fields

“…2 Insects and small swimming organisms have also been levitated acoustically. 3,4 The application of standing acoustic waves for filtering or concentrating [5][6][7] and patterning 8,9 of microscale particles, including cells and bacteria in the size range 0.1À100 lm, has been described. Typically such devices operate in the 1À10 MHz frequency range, corresponding to wavelengths of approximately 1500-150 lm in water.…”

Hydrodynamic Tweezers: 1. Noncontact Trapping of Single Cells Using Steady Streaming Microeddies

“…[19][20][21] Acoustical tweezers (AT) generate trapping forces based on the difference in compressibility between a cell and its medium. [22][23][24][25][26] The absorption of high-frequency acoustic energy (ultrasound) within the cell and fluid generates pressure forces that cause aggregation of cells at pressure nodes or antinodes. OT, DEP, and AT can be designed to allow three-dimensional (3-D) suspension trapping, and they generate strong trapping forces capable of holding motile cells.…”

“…Optical tweezers (OT), introduced by Ashkin over three decades ago, offer the best-known and most widely used means of manipulating single cells in suspension. − Conventional OT use a tightly focused laser beam to generate forces on a cell based on the difference in refractive index between the cell and the medium, and recently developed holographic methods allow spatial control over laser illumination to create trapping arrays and to reduce the impact on cell health by tailoring trap geometry. Dielectrophoretic (DEP) traps create a trapping force by acting on cell polarization induced by an oscillating electrical field. − Acoustical tweezers (AT) generate trapping forces based on the difference in compressibility between a cell and its medium. − The absorption of high-frequency acoustic energy (ultrasound) within the cell and fluid generates pressure forces that cause aggregation of cells at pressure nodes or antinodes. OT, DEP, and AT can be designed to allow three-dimensional (3-D) suspension trapping, and they generate strong trapping forces capable of holding motile cells.…”